Metal roofs with standing seams or simulated standing seams have long been in use in the United States and throughout the world. Standing seam metal roofing can be seen on almost every type of building, from shopping centers to schools, churches to libraries, and skyscrapers to homes. The popularity of standing seam roofing continues to grow because standing seam roofs are weather-tight, energy efficient, durable, cost effective, and environmentally friendly. Standing seam roofs are often made of steel sheets installed at a slope, which assures water runoff and allows snow or ice to easily slide from the roof.
Snow often accumulates on a standing seam roof until the snow and ice melts or until the weight of the snow causes it to slide off the roof. The snow may also slide off the roof when the sun begins to melt the snow from above or heat from the building below melts the snow from beneath. A metal roof may also conduct heat from a part of the roof that is exposed to the sun and this will melt the snow and ice from beneath. As the snow and ice melts, this can produce sliding snow and ice masses. When the snow or ice masses slide off the roof, the snow and ice can come off in large pieces and cause damage to gutters, property, and the roof itself. In some cases, this falling snow and ice can even cause injury or death to people standing underneath the roof. The snow that falls off can also block entrances or curl back and break windows, gas meters, or other building fixtures.
Architects often try to circumvent the danger of snow and ice falling on people and property by adding dormers to a roof design. However, dormers can cause more problems than they fix. Dormers can reduce or eliminate proper ventilation causing ice dams in the valleys and leaks in the roof. Icicles can form easily in the corners and create even greater potential for damage to gutters, roofs, people, and property below. Dormers also increase the points of potential damage on a roof by creating tangents and valleys where snow and ice can strike, and dormers may even be torn off by sliding snow and ice masses.
Some solutions to this problem do not require a change in the design of the building. For example, snow guards or fences can be used in order to try to keep snow banks or ice sheets retained on the roof until they melt. Snow guards have been designed for attaching to the flat surface of the roof, and some snow guards have been designed for attaching to the roof seams. Although the guards or fences may be partially effective, manufacturers do not typically engineer these devices to the fail point of the roof structure or the roofing fasteners. Manufacturers often know when the guard or fence will fail, but do not know when the roofing fasteners, sheathing, the roofing product, or the roof will fail.
In addition, some snow guards and snow fences are not properly engineered to withstand heavy snow loads. When the snow guards or fences strain under the load and break (or come unfastened) these fence and bracket systems often fail completely. This can result in greater property damage and potential risk.